1. Field of Invention
The present invention relates to a small-sized hydroelectric power generating apparatus using water power generated by flow of water passing through a faucet.
2. Related Art
Conventionally, an automatic water faucet apparatus has been it widely known in which a sensor detects the fact that a user holds out his hand below a faucet and on the basis of the detection, water is caused to flow from the faucet. In recent years, an apparatus has also been proposed in which a small-sized hydraulic generator is arranged on a fluid passage of such an automatic water faucet apparatus, the electric power acquired by the small-sized hydroelectric power generating apparatus is stored and power consumption in the circuit such as the above sensor is supplemented with the electric power thus stored (Unexamined Japanese Utility Model Publication Hei. 2-65775).
A brief explanation will be given of the configuration of the small-sized hydraulic generator described above. A waterwheel is arranged on a fluid passage which constitutes a passage for running water. When the waterwheel undergoes hydraulic force of the running water, it rotates. A rotary shaft of the waterwheel is provided with a rotating body fixed integrally. The outer periphery of the rotating body serves as a magnetized rotor magnet which is opposite to a stator pole across a wall of a non-magnetic material. A stator coil is provided so as to cross the magnetic flux passing through the stator pole. When the waterwheel undergone the power of the running water rotates, the rotor magnet rotates relatively to the stator pole. Since the rotor magnet has been magnetized in multiple poles, a change occurs in the flow the magnetic flux passing through the stator. As a result, an electromotive force is generated in the stator coil in the direction of disturbing the change in the flow of the magnetic flux. The electromotive force is rectified and stored in a battery.
Conventionally, in the small-sized hydroelectric power generating apparatus having a structure in which the waterwheel is arranged in the fluid passage, both ends of the rotary shaft of the waterwheel are supported by different members. Specifically, the one end of the rotary shaft is supported by a bearing which is provided within one case body provided with the fluid passage, whereas the other end of the rotary shaft is supported by another bearing which is provided in the other case body covering a power generating portion. The waterwheel, which rotates integrally to the rotary shaft supported by the different members at both ends, is arranged within a space formed when the two case bodies are coupled with each other in the axial direction of the rotary shaft.
Incidentally, the inner wall of the above when the two case bodies are coupled with each other in the axial direction, over the entire periphery of the coupled portion, a sealing member, concretely e.g. a rubber member, for partitioning an internal space from the outside is arranged. The sealing member is pressed by both case bodies. This configuration enhances the degree of sealing the internal space.
However, when both case bodies are coupled with each other by screwing, the pressing force for the sealing member inclines at different positions. Specifically, the pressing force is high in the vicinity of the screwed position whereas it is low at a position remote from the screwed position. Further, both case bodies undergo repelling force of the rubber member squashed by the pressing force.
Because of such inclination of the pressing force and the repelling force, the case bodies may be deformed. When the case bodies are deformed, a problem is presented regarding the accuracy of the rotary shaft which rotates integrally to the waterwheel. Further, the portion which undergoes the low pressing force becomes unstable so that the sealing of the portion becomes to a problem. In addition, because both cases are coupled with each other through the sealing member which may be deformed by pressing as described above, it is difficult to align both case bodies.
In view of the above problems, this invention intends to provide a small-sized hydroelectric power generating apparatus which improves the sealing of a continuous internal space formed when a case body covering a generating portion and another case body forming a fluid passage are coupled with each other, and gives great accuracy of a shaft arranged within the internal space.
In a small-sized hydroelectric power generating apparatus in which a waterwheel arranged in a fluid path and rotating with passage of a prescribed flow rate of fluid, a rotating body coupled with the waterwheel and rotating therewith is used as a rotor portion arranged oppositely to a stator portion, and the rotor portion is rotated relatively to the stator portion with passage of the fluid to generate electric power, the small-sized hydroelectric power generating apparatus according to this invention is provided by including a continuous internal space formed when a first case and a second case are fit to each other, the first case having an inlet and an outlet of the fluid path and the second case having the internal space which communicates with the inlet and outlet and in which the rotating body is arranged and separating the internal space from the stator portion, and in that a concave or convex portion is provided at a fitting portion between the first case and the second case; an opposite wall opposite to the inner wall of the concave portion or the outer wall of the convex portion is provided at the fitting portion between the first case and the second case; a ring-shaped sealing member is provided which is interposed between the opposite wall and the inner wall of the concave portion or the outer wall of the convex portion in a direction orthogonal to the direction of fitting the second case into the first case, and the first case and the second case are provided with supporting portions which support both ends of a shaft supporting the rotating body.
In accordance with this invention, after the first case and second case have been fit to each other, the elastic sealing member is not pressed in the fitting direction, and the elastic sealing member undergoes pressing force from both cases in a direction orthogonal to the fitting direction. Therefore, both cases do not suffer from an inconvenience such as a secular deformation due to elastic repelling force of the elastic sealing member in the fitting direction, and can be arranged at improved accuracy. Hence, the accuracy of the shaft supporting the rotating body and supported by both cases in both ends thereof is also improved. Further, the fitting potion between both cases is difficult to float, thereby improving the sealing of both cases.
In the above invention, the small-sized generator according to another invention is provided in that the opposite wall and the inner wall of the concave portion or the outer wall of the convex portion are formed in parallel to the shaft supporting the rotating body. Therefore, the fitting direction between the first case and the second case is coincident with the axial direction. Thus, the locating accuracy of both cases and shaft accuracy can be further improved.
Further, in the above invention, the small-sized generator according to still another invention is provided in that the first case includes a positioning portion for positioning the second case in a direction orthogonal to the fitting direction of fitting the second case. Therefore, when the first case and second case are fit to each other, the second case is positioned in this direction as well as the fitting direction. Thus, locating accuracy of both cases can be further improved.
Further, in the above invention, the small-sized generator according yet another invention is provided in that the elastic sealing member is arranged to be laminated on the stator portion in the direction orthogonal to the fitting direction.
Further, in the above invention, the small-sized hydroelectric power generating apparatus according to a further invention is provided in that a concave portion is formed at the fitting portion between the first case and the second case, a step is formed on the inner wall of the concave portion, a region located inside the step in a radial direction is used as the positioning portion and the elastic sealing member is arranged on the step.
Further, in the above invention, the small-sized hydroelectric power generating apparatus according to a further invention is provided in that the positioning portion for the second case is provided on a deep side of the step in the fitting direction. Therefore, the operation of placing the elastic sealing member and fitting the second case in the first case can be facilitated.
Further, in the above invention, the small-sized hydroelectric power generating apparatus is provided in that a third case is put on the second case and the stator portion so as to cover them, and the third case is securely screwed to the first case. Therefore, secure fitting between the first case and the second case is reinforced by screwing of the third case to the first case so that coming-off of the first case and second case from each other is prevented. In addition, the third case is put on the stator so as to cover it so that water is prevented from intruding into the stator portion from the outside.